Method for Processing Air

ABSTRACT

A method and apparatus for processing air. The apparatus comprises an air separation module, a first input, a first output, a second output, and a flow control system. The air separation module is configured to generate an inert gas. The first input for the air separation module is configured to receive first air. The first output for the air separation module is configured to output the inert gas from the air separation module. The second output for the air separation module is configured to output separated air from the air separation module. The flow control system is configured to control a flow of air in the air separation module that increases a rate at which the air separation module reaches a desired operating temperature for generating the inert gas using a number of ports in the flow control module.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to aircraft and, in particular,to inert gas generation systems for aircraft. Still more particularly,the present disclosure relates to a method and apparatus for warming anair separation module in an inert gas generation system for an aircraft.

2. Background

Many aircraft have inert gas generation systems. An inert gas generationsystem is used to render a fuel tank in an aircraft substantially inert.In these illustrative examples, fuel tanks may have a space above thefuel in which fuel vapors may be present. This space in the fuel tank isreferred to as an ullage.

Inert gas generation systems are employed to reduce a possibility ofcombustion within the ullage in a fuel tank. Inert gas generationsystems may be used to reduce the oxygen content in these spaces below athreshold needed for combustion. Without sufficient oxygen, fuel vaporsin these locations are unable to ignite.

Inert gas generation systems may introduce an inert gas into theselocations. This inert gas may be a gas, such as nitrogen, nitrogenenriched air, carbon dioxide, and other types of inert gases. With theuse of an inert gas, the oxygen content may be reduced below a thresholdfor combustion.

Inert gas generation systems may employ air separation modules togenerate inert gas. For example, an air separation module may beconfigured to generate an inert gas in the form of nitrogen enriched airfrom the air that is sent into the air separation module. The nitrogenenriched air is air that has higher nitrogen and lower oxygen contentthan the air that is sent into the air separation module.

Some currently available air separation modules include permeablemembranes that separate the oxygen and nitrogen. These permeablemembranes produce inert gas more efficiently above a selectedtemperature or within a selected temperature range. These temperaturesare typically elevated temperatures as compared to the temperature whenthe aircraft is not in use. Material limitations are also present thatpreclude long-term operation above a certain temperature.

Aircraft inert gas generation systems are typically designed to operatenear this temperature limit to reduce the size of the air separationmodule. For example, a permeable membrane in an air separation modulemay have a desired operating temperature of about 170 degrees Fahrenheitand a long-term temperature limit of about 190 degrees Fahrenheit. Theair input into an air separation module may have these temperatures oreven slightly higher temperatures. When an air separation module has notbeen used for some period of time, the temperature within the airseparation module may be lower than the desired temperature.

As a result, a desired temperature for generating nitrogen enriched airat a desired level may not occur until the temperature of the airseparation module reaches a desired temperature for providing a desiredlevel of nitrogen in nitrogen enriched air. This warm-up time may takemore than about 15 minutes before the air separation module is ready tooperate to generate nitrogen enriched air with a desired oxygen level.

This warm-up time may increase the time needed to prepare an aircraftfor operation. As a result, the time needed to prepare an aircraft for aflight may be longer than desired with these warm-up times.

Inert gas generation systems may reduce the warm-up time by using a highflow mode. In a high flow mode, the restriction downstream of the airseparation module is reduced so that the flow rate of nitrogen enrichedair increases. Additionally, the temperature in the air sent into theair separation module also may be increased to reduce the warm-up time.Even with these procedures, the time needed to warm up an air separationmodule may still be longer than desired.

Therefore, it would be desirable to have a method and apparatus thattakes into account at least some of the issues discussed above as wellas possibly other issues.

SUMMARY

In one illustrative embodiment, an apparatus comprises an air separationmodule, a first input, a first output, a second output, a flow controlsystem. The air separation module is configured to generate an inertgas. The first input for the air separation module is configured toreceive first air. The first output for the air separation module isconfigured to output the inert gas from the air separation module. Thesecond output for the air separation module is configured to outputseparated air from the air separation module. The flow control system isconfigured to control a flow of air in the air separation module thatincreases a rate at which the air separation module reaches a desiredoperating temperature for generating the inert gas using a number ofports in the air separation module.

In another illustrative embodiment, an apparatus comprises a fluidseparation module, a first input, an output, and a flow control system.The fluid separation module is configured to generate a desired fluidfrom a first fluid. The first input for the fluid separation module isconfigured to receive the first fluid. The output for the fluidseparation module is configured to output the desired fluid. The flowcontrol system is configured to control a flow of fluids in the fluidseparation module that increases a rate at which the fluid separationmodule reaches a desired temperature for generating the desired fluidusing a number of ports in the fluid separation module.

In yet another illustrative embodiment, a method for processing air ispresent. First air is sent into a first input in an air separationmodule. The air separation module is configured to generate nitrogenenriched air from the first air. Second air is sent into a second inputfor the air separation module. A rate at which the air separation modulereaches a desired operating temperature is increased from a flow of thesecond air in the air separation module.

The features and functions can be achieved independently in variousembodiments of the present disclosure or may be combined in yet otherembodiments in which further details can be seen with reference to thefollowing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the illustrativeembodiments are set forth in the appended claims. The illustrativeembodiments, however, as well as a preferred mode of use, furtherobjectives, and advantages thereof will best be understood by referenceto the following detailed description of an illustrative embodiment ofthe present disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an illustration of an aircraft in accordance with anillustrative embodiment;

FIG. 2 is an illustration of a block diagram of an inert gas generationenvironment in accordance with an illustrative embodiment;

FIG. 3 is an illustration of a block diagram of an air separation modulein accordance with an illustrative embodiment;

FIG. 4 is an illustration of an air separation module in accordance withan illustrative embodiment;

FIG. 5 is an illustration of an air separation module in accordance withan illustrative embodiment;

FIG. 6 is another illustration of an air separation module in accordancewith an illustrative embodiment;

FIG. 7 is an illustration of an air separation module in an inert gasgeneration system in accordance with an illustrative embodiment;

FIG. 8 is an illustration of an air separation module in an inert gasgeneration system in accordance with an illustrative embodiment;

FIG. 9 is an illustration of an air separation module in an inert gasgeneration system in accordance with an illustrative embodiment;

FIG. 10 is an illustration of an air separation module in an inert gasgeneration system in accordance with an illustrative embodiment;

FIG. 11 is an illustration of an air separation module in an inert gasgeneration system in accordance with an illustrative embodiment;

FIG. 12 is an illustration of a block diagram of a fluid separationenvironment in accordance with an illustrative embodiment;

FIG. 13 is an illustration of a flowchart of a process for processingair in an inert gas generation system in accordance with an illustrativeembodiment;

FIG. 14 is an illustration of a flowchart of a process for processingair in an inert gas generation system in accordance with an illustrativeembodiment;

FIG. 15 is an illustration of an aircraft manufacturing and servicemethod in accordance with an illustrative embodiment; and

FIG. 16 is an illustration of an aircraft in which an illustrativeembodiment may be implemented.

DETAILED DESCRIPTION

The different illustrative embodiments recognize and take into account anumber of different considerations. The different illustrativeembodiments recognize and take into account that reducing the warm-uptime for an air separation module may reduce the time needed to sendinert gas into a fuel tank to provide an inert condition for the fueltanks. In this manner, an availability of an aircraft may be made morequickly by reducing the warm-up time for air separation modules.

The different illustrative embodiments recognize and take into accountthat with the current design for an air separation module, an outlet foroxygen enriched air is located closer to the end where the input is forthe air than the end for the output of the nitrogen enriched air. Thedifferent illustrative embodiments recognize and take into account thatthis location of the outlet for the oxygen enriched air may result inless thermal energy available because warm oxygen enriched air exitsthrough this outlet rather than traveling through more areas within theair separation module. The different illustrative embodiments recognizeand take into account that this configuration of inputs and outputs mayresult in more time being needed for warming up the air separationmodule than desired.

Thus, the different illustrative embodiments provide a method andapparatus for warming up an air separation module. In one illustrativeembodiment, an apparatus comprises an air separation module, a firstinput, a first output, a second output, and a second input. The airseparation module is configured to generate an inert gas, such asnitrogen enriched air. The first input for the air separation module isconfigured to receive first air. The first output for the air separationmodule is configured to output the nitrogen enriched air from the airseparation module. The second output for the air separation module isconfigured to output separated air, such as oxygen enriched air, fromthe air separation module. The second input for the air separationmodule is configured to receive second air, wherein the second input forthe air separation module is configured to increase a rate at which theair separation module reaches a desired operating temperature.

With reference now to the figures and, in particular, with reference toFIG. 1, an illustration of an aircraft is depicted in accordance with anillustrative embodiment. Aircraft 100 is an example of a platform inwhich an illustrative embodiment may be implemented.

In this illustrative example, aircraft 100 has wing 102 and wing 104attached to body 106. Additionally, aircraft 100 also has engine 108attached to wing 102 and engine 110 attached to wing 104. Tail 112 ofaircraft 100 has horizontal stabilizer 114, horizontal stabilizer 116,and vertical stabilizer 118. In this illustrative example, wing 102 mayhave fuel tank 120, and wing 104 may have fuel tank 122.

As depicted in these illustrative examples, inert gas generation system124 may be used to send inert gas into fuel tank 120 and fuel tank 122to reduce combustibility in the ullages that may be present within fueltank 120 and fuel tank 122. In particular, an illustrative embodimentmay be implemented in inert gas generation system 124 to reduce anamount of time needed to warm up air separation modules within inert gasgeneration system 124.

With reference now to FIG. 2, an illustration of a block diagram of aninert gas generation environment is depicted in accordance with anillustrative embodiment. In this illustrative example, inert gasgeneration environment 200 comprises platform 202 with fuel tank system204. Aircraft 100 in FIG. 1 is an example of one implementation forplatform 202 in FIG. 2.

In this illustrative example, fuel tank system 204 comprises group offuel tanks 206. A “group”, as used herein, with reference to items,means one or more items. For example, “group of fuel tanks 206” is oneor more fuel tanks.

In this illustrative example, inert gas generation system 208 sendsinert gas 210 into fuel tank system 204. Inert gas 210 reducescombustibility in ullage 212 in fuel tank system 204. Ullage 212 may belocated in group of fuel tanks 206.

Inert gas 210 may be any gas that reduces combustibility of any fuelvapors within group of fuel tanks 206. In this particular illustrativeexample, inert gas 210 takes the form of nitrogen enriched air 214. Inother examples, inert gas 210 may be nitrogen, nitrogen enriched air,carbon dioxide, and other types of inert gases.

In these illustrative examples, inert gas generation system 208generates nitrogen enriched air 214 using air 216 from air source 218.As depicted, air source 218 takes the form of engine 220.

As depicted, inert gas generation system 208 includes heat exchanger222, filter 224, group of air separation modules 226, and distributionsystem 228. In these illustrative examples, air 216 from engine 220 issent to heat exchanger 222. Air 216 may be heated air under pressure. Asdepicted, heat exchanger 222 may reduce a temperature of air 216 to adesirable temperature for use in generating inert gas 210. Air 216 thenpasses through filter 224. Filter 224 is configured to remove undesiredcontaminants within air 216.

Thereafter, air 216 passes through group of air separation modules 226to generate inert gas 210 in the form of nitrogen enriched air 214. Whenpassing through group of air separation modules 226, air 216 may stillbe heated. Air 216 may cause group of air separation modules 226 toreach a desired temperature of operation of group of air separationmodules 226.

Distribution system 228 may be a network of pipes without outlets thatextends through fuel tank system 204. Distribution system 228 isconfigured to send nitrogen enriched air 214 generated by group of airseparation modules 226 into ullage 212 within fuel tank system 204. Inthese illustrative examples, nitrogen enriched air 214 reduces theoxygen in ullage 212 in a manner that reduces combustibility of any fuelvapors within ullage 212.

In these illustrative examples, an illustrative embodiment may beimplemented in one or more of group of air separation modules 226. Inparticular, the flow of air 216 through group of air separation modules226 may be controlled in a manner that reduces time needed to warm upgroup of air separation modules 226. In other words, a rate at whichgroup of air separation modules 226 reaches desired operatingtemperature 232 may be increased in an illustrative embodiment.

With reference now to FIG. 3, an illustration of a block diagram of anair separation module is depicted in accordance with an illustrativeembodiment. As depicted, air separation module 300 is an example of anair separation module within group of air separation modules 226 in FIG.2.

As depicted, air separation module 300 comprises housing 302 withchamber 304. Separation system 306 is located within chamber 304. Inthese illustrative examples, separation system 306 may comprisepermeable membrane system 308. Permeable membrane system 308 may be inthe form of hollow fibers 310. These hollow fibers may be arranged toextend from first end 312 of housing 302 to second end 314 of housing302.

In these illustrative examples, first input 316 is located at first end312. First output 318 is located at second end 314. Second output 320for air separation module 300 is located closer to first input 316 atfirst end 312 than first output 318 at second end 314. Typically, secondoutput 320 is located closer to first input 316 to establishcounter-flow of oxygen enriched air 326, which maximizes the partialpressure difference that drives oxygen permeation along the length ofhollow fibers 310.

In these illustrative examples, first air 322 is input into first input316. First air 322 may be at least a portion of air 216 from engine 220in FIG. 2. In these illustrative examples, first air 322 is heated andalso may be under pressure. First air 322 has a temperature that may beat least desired operating temperature 328 for air separation module300.

In these illustrative examples, first air 322 results in the generationof inert gas 323 and separated air 325. In this particular example,inert gas 323 takes the form of nitrogen enriched air 324, and separatedair 325 takes the form of oxygen enriched air 326.

More specifically, separation system 306 separates first air 322 intonitrogen enriched air 324 and oxygen enriched air 326. Nitrogen enrichedair 324 is air having a higher nitrogen content than first air 322.Oxygen enriched air 326 is air that has a higher oxygen content thanfirst air 322. In these illustrative examples, nitrogen enriched air 324from air separation module 300 is a portion of nitrogen enriched air 214generated by group of air separation modules 226 in FIG. 2.

As depicted, a desired level of nitrogen in nitrogen enriched air 324may be generated by separation system 306 when air separation module 300operates at desired operating temperature 328 for air separation module300. In these illustrative examples, the time needed to reach desiredoperating temperature 328 may take longer than desired, as discussedabove.

The different illustrative embodiments recognize and take into accountthat the flow of first air 322 through first input 316 into hollowfibers 310 may flow in a manner such that the amount of first air 322 isseparated into oxygen enriched air 326 and nitrogen enriched air 324.The flow is such that oxygen enriched air 326 flowing out of hollowfibers 310 and out of second output 320 may be greater than nitrogenenriched air 324 that flows inside hollow fibers 310 along length 336 ofhollow fibers 310 to be output through first output 318.

This reduced amount of nitrogen enriched air 324 flowing through length336 of hollow fibers 310 may result in a longer than desired time toreach desired operating temperature 328. In other words, oxygen enrichedair 326 may not flow along all of length 336 of hollow fibers 310. As aresult, hollow fibers 310 may heat up more slowly with less exposure tooxygen enriched air 326 along length 336 of hollow fibers 310. Morespecifically, portions of hollow fibers 310 closer to second output 320near first end 312 reach desired operating temperature 328, more quicklythan portions closer to first output 318 at second end 314. As a result,hollow fibers 310, as a whole, do not reach desired operatingtemperature 328 as quickly as desired.

Rate 330, at which air separation module 300 reaches desired operatingtemperature 328, may be increased through the use of flow control system338 for air separation module 300. In these illustrative examples, flowcontrol system 338 is configured to receive second air 334 and usesecond air 334 to cause a flow of second air 334 within air separationmodule 300 that increases rate 330 at which air separation module 300reaches desired operating temperature 328. In these illustrativeexamples, second air 334 also is heated and may be under pressure. Thetemperature of second air 334 may be at least desired operatingtemperature 328 in these illustrative examples.

In these illustrative examples, second air 334 flows outside of hollowfibers 310. Further, second air 334 may flow toward second output 320 ina manner that results in greater portions of hollow fibers 310 beingexposed to the heat from second air 334. Second air 334 flows out ofsecond output 320 along with oxygen enriched air 326 generated by firstair 322 in these illustrative examples.

In these illustrative examples, flow control system 338 includes numberof ports 331. Number of ports 331 are associated with air separationmodule 300. In particular, number of ports 331 are in housing 302 in airseparation module 300. In these illustrative examples, number of ports331 may include at least one of second input 332 and third output 341.Additionally, flow control system 338 also may include number ofstructures 340. As depicted, number of structures 340 is associated withsecond input 332.

When one component is “associated” with another component, theassociation is a physical association in these depicted examples. Forexample, a first component may be considered to be associated with asecond component by being secured to the second component, bonded to thesecond component, mounted to the second component, welded to the secondcomponent, fastened to the second component, and/or connected to thesecond component in some other suitable manner. The first component alsomay be connected to the second component using a third component. Thefirst component may also be considered to be associated with the secondcomponent by being formed as part of and/or an extension of the secondcomponent.

In some cases, number of structures 340 may not be associated withsecond input 332. Instead, these structures may be placed at locationswithin chamber 304.

Second input 332 in flow control system 338 is configured to cause aflow of second air 334 through air separation module 300 that increasesrate 330 at which hollow fibers 310 in permeable membrane system 308 inair separation module 300 reach desired operating temperature 328. Theflow of second air 334 also may affect the flow of first air 322 withinchamber 304.

In these illustrative examples, second air 334 flowing through secondinput 332 into air separation module 300 may cause more of first air322, second air 334, or a combination of the two to flow through length336 of hollow fibers 310.

Thus, with the use of flow control system 338, at least one of secondinput 332 and number of structures 340 may cause second air 334 to flowwithin chamber 304 in a manner that increases rate 330 at which airseparation module 300 reaches desired operating temperature 328. Inthese illustrative examples, the flow of second air 334 also may changethe flow of first air 322 in a manner that increases rate 330 in whichair separation module 300 reaches desired operating temperature 328.

As used herein, the phrase “at least one of”, when used with a list ofitems, means different combinations of one or more of the listed itemsmay be used and only one of each item in the list may be needed. Forexample, “at least one of item A, item B, and item C” may include, forexample, without limitation, item A or item A and item B. This examplealso may include item A, item B, and item C, or item B and item C.

In another illustrative example, flow control system 338 may includethird output 341 instead of second input 332. In these illustrativeexamples, third output 341 is located closer to second end 314 thansecond output 320.

As depicted, third output 341 in flow control system 338 is configuredto cause a flow of oxygen enriched air 326 through air separation module300 and out through third output 341 in a manner that increases rate 330at which hollow fibers 310 in permeable membrane system 308 in airseparation module 300 reach desired operating temperature 328. Inparticular, oxygen enriched air 326 may flow outside of hollow fibers310 and along length 336 of hollow fibers 310 in chamber 304 in adirection to third output 341 in these illustrative examples, ratherthan only to second output 320. In other words, the use of third output341 may change the flow of oxygen enriched air 326 within chamber 304 ina manner that increases a rate at which hollow fibers 310 reachesdesired operating temperature 328.

Further, if second input 332 is also present in addition to third output341, second air 334 also may flow through at least one of second output320 and third output 341. With this example, second input 332 may belocated closer to first end 312 than second end 314. The location isselected to reduce the flow of second air 334 that flows directly tothird output 341. In other illustrative examples, third output 341 andsecond input 332 may be placed such that they are farther apart fromeach other and not opposite to each other.

In these illustrative examples, at least one of second input 332 andthird output 341 in flow control system 338 may cause a flow of airwithin separation system 306 in chamber 304 over a greater surface areaof permeable membrane system 308 within chamber 304 in which the airflows. The flow of air may be oxygen enriched air 326, second air 334,or both. In particular, the flow of air is over a greater surface areaon the exterior of hollow fibers 310. This increased flow of oxygenenriched air 326, second air 334, or both over the surface area ofhollow fibers 310 within separation system 306 increases a rate at whichhollow fibers 310 may reach desired operating temperature 328 fromexposure to heat in first air 322 input into first input 316 and secondair 334 input into second input 332.

Thus, flow control system 338 is configured to control a flow of air inair separation module 300 that increases rate 330 at which airseparation module 300 reaches desired operating temperature 328 forgenerating inert gas 323. In these illustrative examples, the air may beat least one of oxygen enriched air 326, nitrogen enriched air 324, andsecond air 334.

The illustration of inert gas generation environment 200 shown in blockform in FIG. 2 and air separation module 300 shown in block form in FIG.3 is not meant to imply physical or architectural limitations to themanner in which an illustrative embodiment may be implemented. Othercomponents in addition to or in place of the ones illustrated may beused. Some components may be unnecessary. Also, the blocks are presentedto illustrate some functional components. One or more of these blocksmay be combined, divided, or combined and divided into different blockswhen implemented in an illustrative embodiment.

For example, although an illustrative embodiment has been described withrespect to aircraft, the illustrative embodiment may be applied to othertypes of platforms. For example, without limitation, other illustrativeembodiments may be applied to a mobile platform, a stationary platform,a land-based structure, an aquatic-based structure, a space-basedstructure, and/or some other suitable platform. More specifically, thedifferent illustrative embodiments may be applied to, for example,without limitation, a submarine, a bus, a personnel carrier, a tank, atrain, an automobile, a spacecraft, a space station, a satellite, asurface ship, a power plant, a manufacturing facility, a building,and/or some other suitable platform in which permeable membranes areused to separate gases.

In still other illustrative examples, other inputs, outputs, orstructures may be included in flow control system 338 in addition toand/or in place of the ones illustrated in these examples. Theseadditional components may be selected to control the flow of heated airwithin air separation module 300 in a manner that increases a rate atwhich air separation module 300 reaches desired operating temperature328. In particular, these components may be selected to provide a flowof heated air within air separation module 300 that exposes greaterportions of hollow fibers 310 to the heated air.

As another illustrative example, other illustrative embodiments may beapplied to other types of inert gas 210 other than nitrogen enriched air214. For example, other gases or fluids may be input into group of airseparation modules 226 to obtain inert gas 210 in other forms. Forexample, the other types of inert gas may be nitrogen, carbon dioxide,and other types of gas that may reduce combustibility of fuel vapors orother vapors in an ullage within fuel tank system 204.

The embodiments illustrated herein depict the bore-side feed hollowfiber permeable membrane air separation modules with the hollow fibersoriented along the axis of the air separation module. These figures aretypical of air separation modules used in aircraft inert gas generationsystems. Other embodiments may use air separation modules that employhollow fibers that are helically wound such that the fibers are orientedat an angle to the axis of the air separation module. Yet otherembodiments may use air separation modules that employ other hollowfiber orientations. Still other embodiments may use shell-side feedhollow fiber permeable membrane air separation modules, air separationdevices that configure the permeable membrane in flat sheets, and otherpackaging methods.

With reference now to FIG. 4, an illustration of an air separationmodule is depicted in accordance with an illustrative embodiment. Inthis illustrative example, air separation module 400 is an example ofone implementation for air separation module 300 in FIG. 3.

As depicted, air separation module 400 comprises housing 402 withchamber 404 inside of housing 402. Separation system 406 is locatedwithin chamber 404 inside of housing 402. In this illustrative example,separation system 406 comprises permeable membrane system 408 in theform of hollow fibers 410.

In this illustrative example, hollow fibers 410 are connected to firsttubesheet 412 at first end 414 of housing 402. Additionally, hollowfibers 410 also are connected to second tubesheet 416 at second end 418of housing 402. These tubesheets may be comprised of epoxy, adhesive, orsome other suitable material. In other illustrative examples, thetubesheets may be structures to which hollow fibers 410 are connected.

The tubesheet is configured such that first air 420 sent into firstinput 422 enters hollow fibers 410 and reduces and/or eliminates flow offirst air 420 between hollow fibers 410 through first tubesheet 412 asfirst air 420 flows through first input 422 into chamber 404. In asimilar fashion, second tubesheet 416 is configured to direct nitrogenenriched air 424 through hollow fibers 410 at second tubesheet 416rather than between hollow fibers 410 when being output through firstoutput 426. However, once first air 420 passes through first tubesheet412, first air 420 may flow through and/or out of hollow fibers 410within chamber 404. In these illustrative examples, second output 428 isconfigured to output oxygen enriched air 430 from air separation module400.

As depicted, hollow fibers 410 are configured to allow first air 420 toflow in the direction of path 432 along the length of hollow fibers 410.The flow of first air 420 in the direction of path 432 means that firstair 420 flows in the direction of path 432 but may not be always on path432. Paths, as depicted in the different illustrative examples, areintended to show general directions of fluid or airflow and not exactpaths that are followed by the fluid or airflow.

As first air 420 flows through hollow fibers 410 past first tubesheet412, hollow fibers 410 are configured to separate first air 420 intonitrogen enriched air 424 and oxygen enriched air 430. The separation offirst air 420 into nitrogen enriched air 424 and oxygen enriched air 430results in oxygen enriched air 430 flowing in a direction of path 434.

For example, hollow fibers 410 are comprised of a membrane configured toallow oxygen molecules to pass through the membrane more readily thannitrogen molecules. Hollow fibers 410 are configured such that lessnitrogen than oxygen passes through the membrane in hollow fibers 410.

As a result, as first air 420 travels in the direction of path 432,first air 420 within hollow fibers 410 has more nitrogen than first air420 sent through first input 422. Additionally, first air 420 travelingthrough the membranes in hollow fibers 410 in a direction of path 434has increased oxygen content as compared to first air 420 entering firstinput 422. Thus, oxygen enriched air 430 is air that has more oxygenthan first air 420. Nitrogen enriched air 424 is air that has morenitrogen than first air 420.

In these illustrative examples, first air 420 is pressurized and heated.First air 420 is considered to be heated when first air 420 has atemperature that is greater than the temperature around air separationmodule 400.

In these illustrative examples, hollow fibers 410 have a desiredoperating temperature at which hollow fibers 410 generate a desiredlevel of nitrogen in nitrogen enriched air 424. When air separationmodule 400 has not been used for some period of time, the temperature ofair separation module 400 may not be at the desired operatingtemperature. In other words, hollow fibers 410 may not be at the desiredoperating temperature for producing nitrogen enriched air 424 at adesired level.

In these illustrative examples, hollow fibers 410 in air separationmodule 400 may be warmed up by sending first air 420 through airseparation module 400. As first air 420 flows through air separationmodule 400, hollow fibers 410 are heated to reach the desired operatingtemperature.

As depicted, the flow of first air 420 through hollow fibers 410 mayresult in the initial warming of the first few inches of hollow fibers410. This situation causes permeation through that small section and mayresult in a significant amount of oxygen enriched air 430 flowing in thedirection of path 434. As a result, the temperature of oxygen enrichedair 430 that exits through second output 428 is not available to warmthe remaining length of hollow fibers 410. As a result, the portion ofhollow fibers 410 closer to second end 418 does not heat up as fast asthe portion of hollow fibers 410 closer to first end 414.

In these illustrative examples, the flow of air along path 432 isnitrogen enriched air 424 flowing inside of hollow fibers 410. The flowof air along path 434 and path 446 is oxygen enriched air 430 flowingoutside of hollow fibers 410. As a result, first air 420 causes moreheating from inside of hollow fibers 410 than outside of hollow fibers410.

In the different illustrative examples, air separation module 400includes flow control system 441. As depicted, flow control system 441comprises second input 442. Second input 442 is configured to receivesecond air 444. Second input 442 is positioned on air separation module400 such that second air 444 changes the flow within air separationmodule 400 in a manner that increases the rate at which air separationmodule 400 reaches a desired operating temperature.

Second air 444 may be from the same source as first air 420 or may beconnected to first output 426. Second air 444 also may be heated and maybe under pressure. Second air 444 sent through second input 442 isconfigured to increase a rate at which air separation module 400 reachesthe desired operating temperature. In particular, the desired operatingtemperature is a desired operating temperature for hollow fibers 410within air separation module 400.

In these illustrative examples, second air 444 flowing through secondinput 442 causes a flow of second air 444 in the direction of path 446.As depicted, second air 444 flows outside hollow fibers 410, while firstair 420 flows inside hollow fibers 410. Second air 444 causes heating ofhollow fibers 410 from the exterior of hollow fibers 410.

As can be seen, path 446 is in a direction upstream towards first end414 of housing 402 and flows through second output 428. As a result, airflow through hollow fibers 410 in a direction of path 446 increases theexposure of hollow fibers 410 to at least one of first air 420 andsecond air 444 through more of the length of hollow fibers 410 thanwithout using second air 444.

In this manner, the temperature of air separation module 400 mayincrease at a greater rate to reach the desired operating temperaturethan without second air 444 flowing through second input 442 in flowcontrol system 441. As a result, the heating of hollow fibers 410 fromthe inside by nitrogen enriched air 424 and from the exterior of oxygenenriched air 430 and second air 444 along paths 432, 434, and 436increases a rate at which air separation module 400 reaches a desiredoperating temperature.

With reference now to FIG. 5, an illustration of an air separationmodule is depicted in accordance with an illustrative embodiment. Airseparation module 500 is an example of another implementation for airseparation module 300 in FIG. 3.

In this illustrative example, air separation module 500 compriseshousing 502 with chamber 504. Separation system 506 is located withinchamber 504. In this illustrative example, separation system 506comprises permeable membrane system 508 in the form of hollow fibers510. Hollow fibers 510 are connected to first tubesheet 512 and secondtubesheet 514.

Further, first input 516 is located at first end 518 of air separationmodule 500. First output 520 is located at second end 522 of airseparation module 500. Air separation module 500 also has second output532 and flow control system 523. As depicted, flow control system 523comprises second input 524 and structure 525.

In these illustrative examples, first air 526 flows through first input516 into air separation module 500. As first air 526 flows in airseparation module 500, first air 526 may be separated into nitrogenenriched air 528, which flows out of first output 520, and oxygenenriched air 530, which flows out of second output 532.

In these illustrative examples, second air 534 may also be sent throughsecond input 524 to warm up air separation module 500. In thisillustrative example, structure 525 comprises hollow ring 536 with holes538 leading into chamber 504. Second input 524 is connected to hollowring 536. As a result, second air 534 flows through second input 524into hollow ring 536 and into chamber 504 through holes 538. Thisconfiguration of second input 524 and structure 525 generates air flowof second air 534 in directions shown by paths 540 in an upstreamdirection from around second end 522 in an upstream direction towardfirst end 518 and through second output 532. As a result, second air 534also flows out of second output 532 along with oxygen enriched air 530.Second air 534 flows outside hollow fibers 510, while first air 526flows inside hollow fibers 510.

Turning now to FIG. 6, another illustration of an air separation moduleis depicted in accordance with an illustrative embodiment. Airseparation module 600 is another example of an implementation for airseparation module 300 in FIG. 3.

In this illustrative example, air separation module 600 compriseshousing 602 with chamber 604. Separation system 606 is located withinchamber 604. Separation system 606 comprises permeable membrane system608 in the form of hollow fibers 610. Hollow fibers 610 are connected atfirst tubesheet 612 and second tubesheet 614. First tubesheet 612 islocated at first end 616 of air separation module 600, while secondtubesheet 614 is located at second end 618 of air separation module 600.

As illustrated, first input 620 is located at first end 616 of airseparation module 600. First output 622 is located at second end 618 ofair separation module 600. Second output 624 is located closer to firstend 616 than second end 618 of air separation module 600.

As depicted, air separation module 600 also includes flow control system625. Flow control system 625 comprises second input 626 and tube 627. Asillustrated, second input 626 is located at second end 618 of airseparation module 600.

In this illustrative example, second input 626 is located concentricallywithin first output 622. Tube 627 is associated with second input 626.Tube 627 is located centrally within chamber 604. Tube 627 extends fromsecond input 626 into first tubesheet 612 at first end 616.

In this illustrative example, first air 628 is sent through first input620. Nitrogen enriched air 630 is output through first output 622.Oxygen enriched air 632 is output through second output 624.

Second air 634 is sent through second input 626 into tube 627. Tube 627has holes 638 located within chamber 604 after second tubesheet 614.Holes 638 allow for second air 634 to flow in the direction of paths640. Second air 634 flows in the direction of paths 640 to exit throughsecond output 624 in these illustrative examples. Second air 634 flowsoutside hollow fibers 610, while first air 628 flows inside hollowfibers 610. As a result, second air 634 is also output through secondoutput 624 along with oxygen enriched air 632.

This flow of second air 634 in an upstream direction provides increasedexposure to longer lengths of hollow fibers 610 to first air 628 andsecond air 634, as compared to when only first air 628 is sent intofirst input 620. In this manner, a rate at which air separation module600 reaches a desired operating temperature may be increased as comparedto only using first air 628 sent through first input 620.

With reference now to FIG. 7, an illustration of an air separationmodule in an inert gas generation system is depicted in accordance withan illustrative embodiment. In this illustrative example, air separationmodule 700 is located in inert gas generation system 702. Air separationmodule 700 may be implemented using air separation module 400 in FIG. 4and may be an example of an implementation for air separation module 300in FIG. 3.

In this illustrative example, air separation module 700 has first input704, first output 706, second output 708, and second input 710 in flowcontrol system 711. Inert gas generation system 702 includes heatexchanger 712, filter 714, and distribution system 716.

In this illustrative example, air 718 flows through pipe 720 into heatexchanger 712. Cooling air 722 may flow through heat exchanger 712 tocool air 718 to a desired temperature. Air 718 flows from heat exchanger712 through pipe 724. Air 718 then flows into air separation module 700through first input 704 via a connection from filter 714 to first input704 by pipe 726.

As depicted, pipe 726 is connected to pipe 728. Pipe 728 also has aconnection to second input 710. First output 706 of air separationmodule 700 is connected to pipe 730, which is also connected to pipe 732before being connected to distribution system 716. Pipe 732 has low floworifice 734, which is configured to reduce a flow of air through pipe732.

In these illustrative examples, valve 740 is located in pipe 720. Valve742 is located in pipe 728. Valve 744 is located in pipe 730. Valve 740may be in an open position or a closed position to control the amount ofair 718 that flows to air separation module 700. The portion of air 718that flows through first input 704 is first air 746. The portion of air718 that flows through pipe 728 is second air 748 in these illustrativeexamples.

Valve 742 can be in an open or closed position and may control theamount of second air 748 that flows into second input 710 in airseparation module 700. Valve 744 controls the amount of nitrogenenriched air 750 that flows into distribution system 716.

During the warm up of air separation module 700, valve 740 is in an openposition. In these illustrative examples, when a valve is in an openposition, the valve may be partially open or fully open. When a valve isin a closed position, the valve is considered to be fully closed. Valve742 also is in an open position.

In these illustrative examples, valve 744 may be in an open position ora closed position during the warm up of air separation module 700. Valve744 may be in a closed position to reduce the flow of nitrogen enrichedair 750 with an undesired quality produced before warm up through pipe730 that enters the fuel tank system through distribution system 716.Valve 744 may be in an open position to increase the flow of warm firstair 746 into nitrogen enriched air 750 through air separation module 700to increase the warming rate.

In one illustrative embodiment, the closing or opening of valve 744 maydepend on whether the fuel tanks are typically already inert onstart-up. For example, if the fuel tank system is already inert, valve744 may be closed to reduce the flow of nitrogen enriched air 750 with apoor quality from entering the fuel tank system.

Placing valve 744 in a closed position does not shut off the flow ofnitrogen enriched air 750 from first output 706 but reduces the flow inthis illustrative example. When valve 744 is in a closed position,nitrogen enriched air 750 output from first output 706 flows throughpipe 732 at a reduced rate as compared to flowing through pipe 730. Whenair separation module 700 has reached a desired operating temperature,valve 742 is moved to a closed position.

Turning now to FIG. 8, an illustration of an air separation module in aninert gas generation system is depicted in accordance with anillustrative embodiment. In this illustrative example, air separationmodule 800 is located in inert gas generation system 802. Air separationmodule 800 may be implemented using air separation module 400 in FIG. 4.

As depicted, air separation module 800 has first input 804, first output806, second output 808, and second input 810. Second input 810 is partof flow control system 811 in air separation module 800. Inert gasgeneration system 802 includes heat exchanger 812, filter 814, anddistribution system 816.

Air 818 enters inert gas generation system 802 through pipe 820, whichis connected to heat exchanger 812. Pipe 821 connects heat exchanger 812to filter 814. Pipe 822 connects filter 814 to first input 804 of airseparation module 800. Pipe 823 connects first output 806 of airseparation module 800 to distribution system 816. Pipe 824 is connectedto pipe 823 and to second input 810 of air separation module 800. Pipe826 is connected to pipe 823.

In these illustrative examples, valve 830 is associated with pipe 820.Valve 832 is associated with pipe 824. Valve 834 and valve 836 areassociated with pipe 823. Pipe 826 has low flow orifice 837.

When air separation module 800 is being warmed up, valve 832 is placedinto an open position to allow a flow of second air 840 into airseparation module 800. This flow of second air 840 is in addition to theflow of first air 842 into air separation module 800. In thisillustrative example, second air 840 is a portion of nitrogen enrichedair 843 output through first output 806. In this example, second air 840is from a downstream source as opposed to the example illustrated inFIG. 7 in which second air 748 was from an upstream source.

In these illustrative examples, when valve 832 is in an open position,valve 834 and valve 836 may both also be in an open position. Further,one or more of these valves may be in a partially closed or completelyclosed position during the warm up of air separation module 800. Whenair separation module 800 has completed warming up, valve 832 may bemoved to a closed position. Thereafter, valve 834 and valve 836 may beselectively moved to an open position to provide a desired amount ofnitrogen enriched air 843 to distribution system 816. When valve 832 isopen, an additional flow area is opened up so that the flow rates offirst air 842 and nitrogen enriched air 843 are increased, with acorresponding increase in the rate of warm up.

With reference now to FIG. 9, an illustration of an air separationmodule in an inert gas generation system is depicted in accordance withan illustrative embodiment. In this illustrative example, air separationmodule 900 is located within inert gas generation system 902. Airseparation module 900 may be implemented using air separation module 400in FIG. 4. Inert gas generation system 902 is an example of animplementation for inert gas generation system 208 in FIG. 2.

In this illustrative example, air separation module 900 has first input904, first output 906, second output 908, and second input 910. Secondinput 910 is part of flow control system 911 for air separation module900.

Inert gas generation system 902 also includes heat exchanger 912, filter914, and distribution system 916.

Pipe 918 receives air 919 and is connected to heat exchanger 912. Pipe920 connects heat exchanger 912 to filter 914. Pipe 922 connects filter914 to first input 904. Air 919 that flows into first input 904 is firstair 923.

Pipe 926 connects first output 906 of air separation module 900 to valve928. Valve 928 is a two-way valve in this illustrative example. Pipe 930is connected to valve 928 and second input 910. Pipe 932 is connected tovalve 928 and distribution system 916. Pipe 934 is connected to pipe932. Pipe 934 has low flow orifice 935.

In these illustrative examples, valve 936 is associated with pipe 918.Valve 938 is associated with pipe 932.

During warm up of air separation module 900, valve 928 may be positionedsuch that nitrogen enriched air 940 flowing out of first output 906 isdirected to flow through pipe 930 into second input 910 as second air942. When the warm up of air separation module 900 has completed, valve938 may then direct nitrogen enriched air 940 flowing out of firstoutput 906 into distribution system 916.

With reference now to FIG. 10, an illustration of an air separationmodule in an inert gas generation system is depicted in accordance withan illustrative embodiment. Air separation module 1000 is located ininert gas generation system 1002. Air separation module 1000 may beimplemented using air separation module 400 in FIG. 4.

In this illustrative example, air separation module 1000 has first input1004, first output 1006, second output 1008, and second input 1010 inflow control system 1011.

Inert gas generation system 1002 also includes heat exchanger 1012,filter 1014, and distribution system 1016. Pipe 1018 is connected toheat exchanger 1012 and receives air 1019. Pipe 1020 connects heatexchanger 1012 to filter 1014. Pipe 1022 connects filter 1014 to firstinput 1004 in air separation module 1000. Air 1019 flowing into firstinput 1004 is first air 1023. Pipe 1024 connects first output 1006 ofair separation module 1000 to distribution system 1016. Pipe 1026 isconnected to pipe 1024 and second input 1010 in air separation module1000. Pipe 1028 is connected to pipe 1024.

Valve 1030 is associated with pipe 1018. Valve 1032 is associated withpipe 1026. Valve 1034 is associated with pipe 1024.

During warm up of air separation module 1000, valve 1032 may be open andvalve 1034 may be closed to cause a flow of nitrogen enriched air 1035from first output 1006 to be second air 1037 input into second input1010. After air separation module 1000 has been heated to a desiredoperating temperature, valve 1032 may be closed, and valve 1034 may bein an open position. When valve 1034 is closed, nitrogen enriched air1035 still flows to distribution system 1016 through pipe 1028. Pipe1028 reduces the flow of nitrogen enriched air 1035 when valve 1034 isin a closed position. The flow of nitrogen enriched air 1035 is reducedby low flow orifice 1029.

With reference now to FIG. 11, an illustration of an air separationmodule in an inert gas generation system is depicted in accordance withan illustrative embodiment. In this illustrative example, air separationmodule 1100 is located in inert gas generation system 1102. Airseparation module 1100 may be implemented using air separation module400 in FIG. 4 and may be an example of an implementation for airseparation module 300 in FIG. 3.

In this illustrative example, air separation module 1100 has first input1104, first output 1106, second output 1108, and third output 1110 inflow control system 1111. Inert gas generation system 1102 includes heatexchanger 1112, filter 1114, and distribution system 1116.

In this illustrative example, air 1118 flows through pipe 1120 into heatexchanger 1112. Cooling air may flow through heat exchanger 1112 to coolair 1118 to a desired temperature. Air 1118 flows from heat exchanger1112 through pipe 1124. Air 1118 then flows into air separation module1100 through first input 1104 via a connection from filter 1114 to firstinput 1104 by pipe 1126.

As depicted, pipe 1128 is connected to second output 1108 and thirdoutput 1110. Pipe 1128 also has output 1129 through which oxygenenriched air 1131 may flow.

First output 1106 of air separation module 1100 is connected to pipe1130, which is also connected to pipe 1132 before being connected todistribution system 1116. Pipe 1132 has low flow orifice 1134, which isconfigured to reduce a flow of air through pipe 1132.

In these illustrative examples, valve 1140 is located in pipe 1120.Valve 1142 and valve 1143 are located in pipe 1128. Valve 1144 islocated in pipe 1130. Valve 1140 may be in an open position or a closedposition to control the amount of air 1118 that flows to air separationmodule 1100. The portion of air 1118 that flows through first input 1104is first air 1146.

Valve 1142 may be in an open or closed position to control the amount ofoxygen enriched air 1131 that exits from second output 1108. Valve 1143may be in an open or closed position to control the amount of oxygenenriched air 1131 that exits third output 1110. Valve 1144 controls theamount of nitrogen enriched air 1150 that flows into distribution system1116.

During warm up of air separation module 1100, valve 1140 is in an openposition. Valve 1142 is in a closed position, and valve 1143 is in anopen position.

In these illustrative examples, valve 1144 may be in an open position ora closed position during the warm up of air separation module 1100.Valve 1144 may be in a closed position to reduce the flow of nitrogenenriched air 1150 with an undesired quality produced before warm upthrough pipe 1130 that enters the fuel tank system through distributionsystem 1116. Valve 1144 may be in an open position to increase the flowof first air 1146 into nitrogen enriched air 1150 through air separationmodule 1100 to increase the warming rate.

Placing valve 1144 in a closed position does not shut off the flow ofnitrogen enriched air 1150 from first output 1106 but reduces the flow.When valve 1144 is in a closed position, nitrogen enriched air 1150output from first output 1106 flows through pipe 1132 at a reduced rateas compared to flowing through pipe 1130. When air separation module1100 has reached a desired operating temperature, valve 1142 is moved toan open position, and valve 1143 is moved to a closed position.

In these illustrative examples, the addition of third output 1110 inflow control system 1111 controls the flow of first air 1146 through airseparation module 1100 in a manner that results in air separation module1100 warming up more quickly than if third output 1110 was not presentor used. For example, the flow of oxygen enriched air 1131 within airseparation module 1100 to provide the flow of oxygen enriched air 1131through second output 1108 and the flow of oxygen enriched air 1131through third output 1110 in a manner that increases a rate at which airseparation module 1100 warms up to a desired temperature to generatenitrogen enriched air 1150 at first output 1106. With the use of thirdoutput 1110, more of oxygen enriched air 1131 may flow through thelength of air separation module 1100 than if valve 1143 is closed andprevents oxygen enriched air 1131 from flowing through third output1110.

Turning now to FIG. 12, an illustration of a block diagram of a fluidseparation environment is depicted in accordance with an illustrativeembodiment. In this illustrative example, platform 1202 in fluidseparation environment 1200 has fluid separation system 1204. Fluidseparation system 1204 includes group of fluid separation modules 1206.Group of fluid separation modules 1206 may be configured to separatefirst fluid 1208 into fluids 1210. In these illustrative examples, firstfluid 1208 may be a heated fluid.

Fluid separation module 1212 is an example of a fluid separation modulein group of fluid separation modules 1206. Fluid separation module 1212is configured to output desired fluid 1213.

Fluid separation module 1212 has first input 1214, first output 1216,and flow control system 1217. Flow control system 1217 includes numberof ports 1221. Number of ports 1221 are in fluid separation module 1212.As depicted, number of ports 1221 include at least one of second input1218 and third output 1228 in these illustrative examples. Flow controlsystem 1217 also may include number of structures 1219. These structuresmay be associated with second input 1218. Flow control system 1217 isconfigured to control a flow of fluids 1210 in fluid separation module1212. The control of the flow of fluids 1210 in fluid separation module1212 is configured to increase a rate at which fluid separation module1212 reaches desired operating temperature 1224.

As depicted, first fluid 1208 is sent into first input 1214. Desiredfluid 1213 is output through first output 1216 in these illustrativeexamples. Second input 1218 is configured to receive second fluid 1222.Second fluid 1222 is a heated fluid in this illustrative example. Secondinput 1218 in flow control system 1217 is configured to cause secondfluid 1222 to become separated into fluids 1210 and flow within fluidseparation module 1212 in a manner that increases a rate at which fluidseparation module 1212 reaches desired operating temperature 1224. Inthese illustrative examples, fluid separation module 1212 also may havesecond output 1226 in some illustrative examples through which firstseparated fluid 1227 may flow.

In some illustrative examples, flow control system 1217 also may includethird output 1228. Second separated fluid 1230 may flow out of thirdoutput 1228. Third output 1228 may be configured to cause a flow offluids 1210 within fluid separation module 1212 in a manner thatincreases a rate at which fluid separation module 1212 reaches desiredoperating temperature 1224.

The use of at least one of second input 1218 and third output 1228 mayincrease the area in which fluids 1210 flow in fluid separation module1212. In other words, either second input 1218, third output 1228, orboth may be used with fluid separation module 1212. In other words, theflow of fluids 1210 may be more even through fluid separation module1212 with the use of flow control system 1217.

The illustration of an aircraft in FIG. 1 and components in an inert gasgeneration system in FIGS. 4-11 may be combined with componentsillustrated in FIGS. 2, 3, and 12, used with components in FIGS. 2, 3,and 12, or a combination of the two. Additionally, some of thecomponents in FIGS. 1 and 4-11 may be illustrative examples of howcomponents shown in block form in FIGS. 2, 3, and 12 can be implementedas physical structures.

With reference now to FIG. 13, an illustration of a flowchart of aprocess for processing air in an inert gas generation system is depictedin accordance with an illustrative embodiment. This process may beimplemented in air separation module 300 in FIG. 3.

The process begins by sending first air into a first input in an airseparation module (operation 1300). The first air may be first air 322in FIG. 3. The air separation module is configured to generate nitrogenenriched air from the first air. Second air is sent into a second inputfor a flow control system for the air separation module (operation1302). The flow control system may be flow control system 338, and thesecond air may be second air 334 in FIG. 3. In these illustrativeexamples, the flow control system also may include a number ofstructures associated with the second input.

The process then increases a rate at which the air separation modulereaches a desired operating temperature from the flow of the second airin the air separation module (operation 1304), with the processterminating thereafter.

In these illustrative examples, the flow of the first air, the oxygenenriched air, and the nitrogen enriched air within the air separationmodule causes the air separation module to reach the desired operatingtemperature more quickly than without the second air.

With reference now to FIG. 14, an illustration of a flowchart of aprocess for processing air in an inert gas generation system is depictedin accordance with an illustrative embodiment. This process may beimplemented in air separation module 300 in FIG. 3. This process may beimplemented using a number of ports associated with the air separationmodule. In these illustrative examples, the number of ports may be, forexample, at least one of second input 332 and third output 341 in flowcontrol system 338 in FIG. 3. In other words, one or both of these portsmay be used in the illustrative examples.

The process begins by sending first air into a first input in an airseparation module (operation 1400). The first air may be first air 322in FIG. 3. The air separation module is configured to generate nitrogenenriched air from the first air. The process outputs the nitrogenenriched air at a first output in the air separation module (operation1402). The nitrogen enriched air may be nitrogen enriched air 324 inFIG. 3.

The process disables the output of oxygen enriched air from a secondoutput in the air separation module (operation 1404) and outputs oxygenenriched air from a third output in the air separation module (operation1405). The second output may be second output 320, and the third outputmay be third output 341 in FIG. 3. The oxygen enriched air may be oxygenenriched air 326 in FIG. 3. The oxygen enriched air is a separated airgenerated from separating the nitrogen enriched air from the first air.

A determination is made as to whether the air separation module hasreached a desired operating temperature (operation 1406). Thisdetermination may be made based on one or more of temperaturemeasurement, oxygen concentration measurement of the nitrogen enrichedair, oxygen concentration measurement of the oxygen enriched air, apredetermined warm-up time, a warm-up time that is a function of ambienttemperature, flow rate measurement of the oxygen enriched air, flow ratemeasurement of the inlet air, or other suitable factors.

If the air separation module has not reached a desired operatingtemperature, the process outputs oxygen enriched air from the thirdoutput in the air separation module (operation 1408), with the processreturning to operation 1400. In these illustrative examples, the thirdoutput is a component in a flow control system that is used when warmingup the air separation module to a desired operating temperature. A thirdoutput may be disabled when the air separation module reaches a desiredoperating temperature.

With reference again to operation 1406, if the air separation module hasreached the desired operating temperature, the process outputs theoxygen enriched air from second output in the air separation module(operation 1410) and disables the output of the oxygen enriched air fromthe third output in the air separation module (operation 1412), with theprocess returning to operation 1400.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatuses and methods in an illustrativeembodiment. In this regard, each block in the flowcharts or blockdiagrams may represent a module, segment, function, and/or a portion ofan operation or step. In some alternative implementations of anillustrative embodiment, the function or functions noted in the blocksmay occur out of the order noted in the figures. For example, in somecases, two blocks shown in succession may be executed substantiallyconcurrently, or the blocks may sometimes be performed in the reverseorder, depending upon the functionality involved. Also, other blocks maybe added in addition to the illustrated blocks in a flowchart or blockdiagram.

Although the different illustrative examples have been described withrespect to separating air to form an inert gas, the differentillustrative embodiments may be applied to other types of fluidseparation systems other than those for separating air into oxygenenriched air and nitrogen enriched air.

Illustrative embodiments of the disclosure may be described in thecontext of aircraft manufacturing and service method 1500 as shown inFIG. 15 and aircraft 1600 as shown in FIG. 16. Turning first to FIG. 15,an illustration of an aircraft manufacturing and service method isdepicted in accordance with an illustrative embodiment. Duringpre-production, aircraft manufacturing and service method 1500 mayinclude specification and design 1502 of aircraft 1600 in FIG. 16 andmaterial procurement 1504.

During production, component and subassembly manufacturing 1506 andsystem integration 1508 of aircraft 1600 takes place. Thereafter,aircraft 1600 may go through certification and delivery 1510 in order tobe placed in service 1512. While in service 1512 by a customer, aircraft1600 in FIG. 16 is scheduled for routine maintenance and service 1514,which may include modification, reconfiguration, refurbishment, andother maintenance or service.

Each of the processes of aircraft manufacturing and service method 1500may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of vendors, subcontractors, and suppliers; and anoperator may be an airline, a leasing company, a military entity, aservice organization, and so on.

With reference now to FIG. 16, an illustration of an aircraft isdepicted in which an illustrative embodiment may be implemented. In thisexample, aircraft 1600 is produced by aircraft manufacturing and servicemethod 1500 in FIG. 15 and may include airframe 1602 with plurality ofsystems 1604 and interior 1606. Examples of systems 1604 include one ormore of propulsion system 1608, electrical system 1610, hydraulic system1612, and environmental system 1614. Any number of other systems may beincluded. Although an aerospace example is shown, different illustrativeembodiments may be applied to other industries, such as the automotiveindustry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of aircraft manufacturing and service method 1500 inFIG. 15. In one illustrative example, components or subassembliesproduced in component and subassembly manufacturing 1506 in FIG. 15 maybe fabricated or manufactured in a manner similar to components orsubassemblies produced while aircraft 1600 is in service 1512 in FIG.15. For example, air separation modules may be manufactured inaccordance with an illustrative embodiment to include a flow controlsystem.

As yet another example, one or more apparatus embodiments, methodembodiments, or a combination thereof may be utilized during productionstages, such as component and subassembly manufacturing 1506 and systemintegration 1508 in FIG. 15. One or more apparatus embodiments, methodembodiments, or a combination thereof may be utilized while aircraft1600 is in service 1512 and/or during maintenance and service 1514 inFIG. 15. Air separation modules manufactured in accordance with anillustrative embodiment may be added to an inert gas generation systemalready present in an aircraft while aircraft 1600 is in service 1512 orin maintenance and service 1514. Further, an air separation module inaccordance with an illustrative embodiment may be used as part of anupgrade or refurbishment of an aircraft when an inert gas generationsystem is added to the aircraft.

Thus, the different illustrative embodiments may reduce the time neededfor an air separation module to warm up to a desired operatingtemperature. The different illustrative embodiments employ a flowcontrol system that changes the flow of air through an air separationmodule that causes the air separation module to warm up more quicklythan without the flow control system. In these illustrative examples, asecond air is input into the air separation module in addition to thefirst air normally input into the air separation module. The second airis input in a location that allows for more of the permeable membranesin the hollow fibers to be exposed to more airflow of at least one ofthe first air and one of the second air.

The description of the different illustrative embodiments has beenpresented for purposes of illustration and description and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different illustrativeembodiments may provide different advantages as compared to otherillustrative embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

1-17. (canceled)
 18. A method for processing air, the method comprising:sending first air into a first input in an air separation module,wherein the air separation module is configured to generate nitrogenenriched air from the first air; outputting nitrogen enriched air at afirst output in the air separation module; outputting oxygen enrichedair at a second output; and increasing a rate at which the airseparation module reaches a desired operating temperature using a numberof ports in the air separation module.
 19. The method of claim 18,wherein the number of ports comprises: a second input for the airseparation module, wherein the second input is configured to receivesecond air, wherein the second input is configured to increase the rateat which the air separation module reaches the desired operatingtemperature.
 20. The method of claim 18, wherein the number of portscomprises: a third output for the air separation module wherein thethird output is configured to output the separated air and the thirdoutput is configured to increase the rate at which the air separationmodule reaches the desired operating temperature.
 21. The method ofclaim 18, wherein the number of ports comprises a second input for theair separation module, the second input configured to receive second airfrom a heating source.
 22. The method of claim 21 further comprising:diverting, using a pipe downstream from the first output, at least aportion of the nitrogen enriched air to the air separation module